No matter how many lights or suns I add, this shiny model stays dark
Wild stab in the dark:

I think you only have mostly reflecting materials in the scene. They act as mirrors and mirrors are only as bright as the stuff they can reflect. You don't have anything bright in your scene to reflect. Just for fun, add a few big planes with diffuse shaders into the scene that are sufficiently lit and see if there's a difference. Alternatively you could crank up the brightness of the world color which, right now, is what gets reflected.

Your lamps seem to work fine since the small areas where they reflect into the camera are burnt white. Problem with mirrors is that they only show the light when the lamp is on the other side of the mirror with matching angles so that it can reflect into the camera. think of where the sun is on a sunset at the beach.

Another way is to use a mix shader (glossy/diffuse). That'll help directing much more light into the camera.